Traditionally, when refrigerant charged refrigeration systems were repaired, the refrigerant charge was simply loosed to the atmosphere as necessary to accomplish the repairs. Recently, it has become increasingly desirable to capture and reuse the refrigerant charges for a number of reasons; refrigerant pollution of the atmosphere is perceived as environmentally destructive, government regulations now limit the release of fluorocarbon refrigerants to the atmosphere, and the cost of refrigerant materials has increased making the disposal and replacement of the refrigerant charge increasingly costly.
Refrigerant recovery devices generally compress and cool refrigerant storage cansiters. Many of these systems have refrigerant storage canisters. Many of these systems have purification elements, such as filters, to remove contaminants from the used refrigerant during the removal-compression-cooling process.
Removal and purification of a refrigerant charge from a large refrigeration system can be a lengthily process. However, if the operator of recovery and purification apparatus of the present art leaves the apparatus unattended, a system failure may occur resulting in a shutdown of the recovery operation which will not be discovered until the operator returns. This will result in a longer overall time to complete the recovery operation than had been anticipated. This is of particular concern where time is of the essence in completing refrigeration system repairs, as when perishable commodities are at risk. Further, in such operations, should completion of the recovery operation occur more quickly than had been anticipated, the advantage of earlier completion will be lost.